Copy machine cooling and drying system

ABSTRACT

A copy machine cooling and drying system includes blower means mounted in the scanning chamber of a copy machine and operative to drive air from the chamber into a duct defined along a light tunnel wall and discharging in drying relation onto copy sheets after emergence from liquid developer. A balanced dual blower system is provided. Heretofore wasted tunnel space is utilized in the duct for transferring the air from the blowers to discharge from the duct. Such discharge is through an especially efficient arrangement of distribution ports. At least part of the duct structure provides copy sheet directing means. Start-up booster heating is provided.

0 United States Patent 1 1 1111 2,762,812

Wolff et al. Oct. 2, W73

[54] COPY MACHINE COOLING AND DRYlNG 3,583,805 6/1971 Tanaka 355/30 XSYSTEM [76] Inventors: David F. Wolfii, 21 w. 474 22nd St.,

Glen Ellyn "L 60137 Raymond J- Asslslant Exammer-M1chael D. Hams MM 6Potomac Ave Atr0rneyBenjam|n l-lv Sherman et al.

9 '7 Chicago, Ill. 6065] [57] ABSTRACT [22] Filed' June 1972 A copymachine cooling and drying system includes [21] Appl. No.: 263,857blower means mounted in the scanning chamber of a copy machine andoperative to drive air from the U 5 Cl 355/10 355/30 chamber into a ductdefined along a light tunnel wall 5 13/) and discharging in dryingrelation onto copy sheets [58] Fie'ld "fig 30 after emergence fromliquid developer. A balanced dual blower system is provided. Heretoforewasted tunnel space is utilized in the duct for transferring the air[56] References Cited from the blowers to discharge from the duct. Suchdis- UNITED STATES PATENTS charge is through an especially efficientarrangement of 3.637.304 l/ Tig r 355/2 X distribution ports. At leastpart of the duct structure 3,598,486 8/!97! Kush1ma.. 355/30 X providescopy sheet directing means. Start-up booster 3,33(),l89 7/l967 Vll355/10 heating is provided 3,517,997 6/1970 Ghlselll.... 355/30 X3,352,218 11/1967 Ostensen 355/27 x 18 Claims, 4 Drawing FiguresPATENTED OCT 2 75 SHEET 10F 2 Jm w w PATENIEU 2' sum 2 or 2 COPYMACHIINE COOLING ANlD DIRYHNG SYSTEM This invention relates to copymachine cooling and drying system and is more particularly concernedwith an arrangement especially suitable for compact desk model liquiddevelopment electrostatic copiers.

A continuing problem in liquid development copiers has been sufficientlyrapid drying of the copies produced at high speed and relatively shorttravel distance from the developing station to the receiving station.Although overhead drying air supply directed downwardly against the dampdeveloped copy sheet has been used with some success, prior systems havebeen less efficient than desired. Although there has been use made ofscanning lamp heat to warm the air then directed into drying relationwith the damp copy sheets, a serious problem has persisted duringstart-up before the air in the vicinity of the lamp has been warmed toan efficient degree. Another problem has been that of providingsufficient volume of drying air in a properly applied manner to the dampcopy sheets. Yet another problem has resided in that the duct work forconducting the air from source to point of projection toward the dampcopy sheets has required excessive headroom or has been sacrified involumetric capacity to attain compactness in the associated'machine.

Accordingly, an important object of the present invention is to overcomethe foregoing and other disadvantages, deficiencies, inefficiencies,shortcomings and problems in prior structure and to attain importantadvantages and improvements as will hereinafter become apparent.

Another object of the invention is to provide a new and improved dryingair duct means in a wet development copier.

A further object of the invention is to provide a new and improved lighttunnel and air duct structure in a copymaking machine.

Still another object of the invention is to provide an especiallyefficient drying air distribution and projection arrangement for wetdevelopment copymaking machines.

Yet another object of the invention is to improve the volume anddistribution of the drying air supply for treating damp copy sheets in acopier.

A yet further object of the invention is to provide an efficientstart-up booster heating arrangement for the drying air supply in a dampdevelopment copymaking machine.

A still further object of the invention is to provide new and improvedmeans for cooling an electrostatic copier and utilizing the air warmedby the scanning chamber lamp for drying damp copy sheets after wetdevelopment.

Other objects, features and advantages of the invention will be readilyapparent from the following description of a preferred embodimentthereof, taken in conjunction with the accompanying drawings, althoughvariations and modifications may be effected without departing from thespirit and scope of the novel concepts embodied in the disclosure, andin which:

FIG. 11 is a generally schematic side elevational view of a copymakingmachine showing features of the invention;

FIG. 2 is an isometric view showing the air duct system;

FIG. 3 is a fragmentary enlarged plan view taken substantially in theplane of line lll-lIl of HO 1; and

FIG. 4 is a fragmentary enlarged plan view taken substantially in theplane of line lV-lV of FlG. ll.

On reference to FIG. 1, a copymaking machine 5 is shown by way ofexample, more-or-less schematically, and comprises a relatively small,compact desk model electrostatic copier housed within a cabinet 7.Within the cabinet is provided a scanning chamber 8, in this instance inthe front upper portion of the cabinet, including means in the upperportion thereof defining a scanning aperture 9 at which a document to becopied is scanned. As shown, the scanning aperture 9 is associated withtransport means in this instance comprising a transport system includingdriven rollers, but this aperture may be of any other desired form suchas a full scanning window, a book copier arrangement over which areciprocating carriage transports the document or other object to becopier, or the like. Whatever the form or disposition of the scanningaperture 9, light produced by a lamp 111 is concentrated by a reflector12 into the scanning aperture to illuminate the object of which thesurface presented at the aperture is to be copied by scanning through anoptical system which projects the scanned image onto a copy sheet.Herein this is effected by means of a mirror 13 mounted in the lowerfront portion of the scanning chamber 8 and which projects the scannedimage rearwardly through a lens system l4 located at the front of alight tunnel l5 and extending rearwardly and upwardly to an exposureaperture 17. Copy sheets 18 are transported as by means of driven setsof rollers 19 from a suitable supply such as a stack of cut sheets froma magazine in the upper portion of the cabinet or from a supply roll 20first through an electrostatic corona discharge device 21 and thenacross the exposure aperture 17 where the projected image is impressedon the charged sheet surface. From the exposure aperture 17, the exposedcopy sheets l3 and transported by means such as rollers 22 through wetdeveloper means, herein comprising a developer tray 23 suitably suppliedwith liquid and suspended toner. At the discharge side of the developertray 23, the developed copy sheets K3 are drivingly engaged and squeezedby means such as rollers 24 which advance the damp sheets forwardly overa downwardly and forwardly slanting ramp 25 having at its forward endfeed-out roller means 27 which advance the copy sheet on under a pivotedhold-down 23 over a ramp extension 29 which leads to a copy sheetreceptacle tray 30 in a receiving space 31 under the exposure chamber 8and freely accessible at the front of the machine cabinet. Separatingthe exposure chamber 8 from the receiving space and providing a lightbarrier is a front panel 32 and a separating panel 33, the latterextending from the lower end of the front panel 32 and rearwardlytherefrom spaced above the ramp 25 and the extension 29 and providing acopy paper chute leading to the front of the cabinet. Mounting of thepanels 32 and 33 within the cabinet is to and between opposite parallelvertical frame panels 34 (FIGS. l. and 2), the panel 33, at least, beingprovided with suitable upstanding side attachment flanges 35 and 37which are se cured as by means of screws 33 to the frame panels 34.

In addition to its chamber separatiang and light shielding function, thepanel 33 is constructed and arranged to serve as an important part of anair duct system for cooling the illumination and scanning chamber 8 anddrying the devloped copy sheets 18 after they leave the developer tray23. To this end, the plate 33, which serves as a roof for the copy sheetexit chute, operates with the bottom wall of the light tunnel providedby a plate 39 to define an air duct system 40 leading to adjacentterminating adjacdent the feed-out rollers 24 at the developer station.ln a desirable arrangement, the bottom panel 39 of the light tunnelcooperates with a top panel 41, both of the panels being of a width toextend fully between the vertical frame panels 34. At its forward endthe top panel 41 is supported on a transverse frame bracket bar 42 whichalso supports the lens assembly 14. At its rear end the panel 15 issupported by a transverse bracket bar 43 which also serves as the upperside of the exposure aperture. Similarly, the rear end of the bottomtunnel panel 39 is supported by a transverse bracket bar 44 which servesas the bottom edge of the exposure aperture. At its front end portion,the panel 39 underlies the lens assembly l4 and has a downturned spacerand attachment flange 45 which defines a shallow air duct gap spacedrelationship to the underlying panel 33 and is secured as by means ofscrews 47 to the lower end portion of a rear closure panel 48 for thelight chamber 8 extending from the scanning aperture 9 to the panel 33,with a suitable opening therein to accommodate light beam access fromthe mirror 13 to the lens system 14.

For large volume cooling air circulation through the chamber 8 andcorrespondingly large volume drying air delivery to the air duct system40, blower means are mounted in the lower part of the chamber 8,desirably comprising a pair of squirrel cage blowers 49 respectivelymounted one on each of the frame panels 34 and each driven by arespective motor 50, with the intake opening from each of the blowerhousings exposed to the interior of the chamber 8 so that the air whichis drawn into the respective blowers will circulate past the lamp 11 asfor example through air entry openings 51 in the frame panels 34generally aligned with the portion of the chamber 8 where the greatestheat is generated in the operation of the lamp 11. Thereby large volumeof air is drawn into the chamber 8 in the operation of the blowers 49not only through the openings 51 but other openings such as in thevicinity of the exposure aperture 9, etc., for cooling circulationthrough the chamber 8, with exhaust from the blowers 49 being into thedrying air duct system 40.

In order to accommodate respective exhaust nozzles 52 from the blowers49, and to assist in directing the air for most efficient application tothe damp copy sheets for drying the same, while maintaining the utmostcompactness of structure, means are provided forming respective air ductlead-in passages 53 along the opposite sides of the tunnel 15 andcommunicating with the respective discharge nozzles. In a simple,economical and efficient construction, each of the lead-in passages isdesirably formed in the tunnel lower panel 39. Accordingly, this panelis desirably constructed from a sheet metal plate which has respectiveopposite side marginal portions partially severed along longitudiallines from the front end of the panel to adjacent but spaced from therear end of the panel and providing a passage roof 54 offset by bendingthe same up from the main plane of the panel along the line of the rearend juncture thereof with the panel body sufficiently to accommodate theheight of the associated nozzle 52 as well as being of a width toaccommodate the width of the nozzle. To close the inner sides of thepassages 53 from the inside of the light tunnel l5, respective elongatedtriangular closure plates 55 are mounted between the inner edges of themarginal sections 54 and the adjacent edges of the body of the panel 39from which severed, angular longitudinal outwardly projecting respectiveattachment flanges 57 on the offset enclosure plates being attached tothe sections 54 and inwardly angular respective longitudinal attachmentflanges 58 on the plates being fixedly secured to the body of the panel39. Along their longitudinal outer edges, the offset panel sections 54are provided with respective attachment flanges 59 secured as by meansof screws 60 to the contiguous frame panel 34.

At their rear ends, the duct passages 53 terminate in the plane of thepanel 39 generally vertically above the feed-out rollers 24. As a resultof the diminishing cross sectional flow area of the passageways 53 fromtheir inlet ends at the discharge nozzles 52 to the rear ends of thepassageways, and by having the area of the duct system 40 which providesa relatively flattened plenum chamber of gradually diminishing crosssectional flow area from the front end toward the rear .end, theprogressive restriction causes gradual increase in air pressure forefficient drying discharge onto the damp copy sheets passing thereunderin the copy sheet delivery passageway chute over the ramp 25.

To implement and improve distribution and direction of the thuspressurized air from the blowers 49 onto the copy sheets, the rear endportion of the duct panel 33 is provided with an efficient pattern ofair distribution and delivery ports 60. For best results, due to therelative concentration of air in this area from the two deliverypassages 53, the ports are provided in two identical, balanced relationgroups of perforations each of which groups covers a similar area, inrelatively transversely spaced relation, of the panel 33 overlying theramp 25. For example, where the total width of the panel 33 is about 12%inches, each of the groups perforations, arranged in generallypentagonal shape may extend a little over 4 inches in any direction witha uniform number of the perforations such as 194 holes onequarter inchin diameter in each group with the perforations uniformly distributed ineach group.

By preference the duct plate 33 extends short of the total length ofduct desired, and a combination duct terminal and deflector plate 61provided of a width to extend fully between the frame panels 34 and of alength to underlap the rear end of the panel 33 and to extend intooverlying relation to the feed-out rollers 24. In a desirableconfiguration, the plate 61 has a front end lip flange 62 which engagesagainst an underturned reinforcing flange along the rear edge of thepanel 33. Rearwardly from the lip flange 62 the plate 61 is maintainedin spaced relation to the underface of the tunnel panel 39 by means ofan offsetting flange 63 joining an attachment flange 64 along the rearmargin of the plate. Attachment of the flange 64 to the panel 39 is bymeans of screws 65 extending through screw holes 67 in the flange andtapped into corresponding screw holes 68 in the panel 39. Through thisarrangement, the plate 61 provides a rearward extension of the plenumand duct passages 53 provided between the panels 33 and 39 and alsoserves as a rear closure for the plenum. In addition, the plate 61provides an extension of the drying air delivery and distribution portsystem from the delivery duct system, being for this purpose provided inthat area thereof between the flanges 62 and 63 with a pattern of aplurality of port perforations 69. For example, there may be 32 of theholes 69 of about one-half inch in diameter, located in desirable groupsalong the width of the perforated area, in a uniformly balancedrelationship and located to issue the air downwardly against the damp,developed copy sheets as they are advanced from the rollers 24, and withthe juncture of the offsetting flange 63 with the perforated body of theplate relatively close to the upper of the rollers 24 so that therollers provide, in effect, a barrier, together with the imperforateoffsetting flange 63, against rearward travel of the drying air, thusprotecting the developer tray against evaporating effect of such air,and taking advantage of the air for its intended purpose, namely dryingthe copy sheets efficiently and rapidly.

in addition to its air distribution function, the plenum terminal andair distribution plate oil conveniently serves as a copy sheet deflectortoward which the copy sheets are directed by the rollers 24 in agenerally upward and forward direction and from which the sheets thenturn downwardly and forwardly to the ramp 25 and onward into the nip ofthe rollers 27. To avoid closing of the ports 69 and to prevent anytendency for adherence of damp or wet copy sheets to the deflectorsurface of the plate oil, the plate is provided with a plurality oflongitudinally extending downwardly project-' ing deflector ribs 70desirably uniformly spaced across the body of the plate between groupsof the perforations 69. Beyond the forward ends of the ribs 70, if theleading end of a copy sheet has not already turned downwardly toward theramp 25, the front end flange 62 serves a further deflecting functionand for this purpose is desirably turned obliquely generally downwardlyand forwardly, and by the spaced relation of the forward end of theflange from the adjacent portion of the panel 33 positively deflects theleading end of the copy sheet away from the panel 33 and toward the ramp25.

At cold start-up of the machine, only cold air will be initially derivedfrom the scanning chamber 8 by way of the blowers 49, resulting in slowand possibly inadequate drying of the first produced copy sheets.Accordingly, until sufficient heat has been generated by operation ofthe lamp ill to raise the air temperature sufficiently for efficientdrying, means are provided for heating the air downstream from theblowers, in the duct passages 53, and also serving for booster heatingshould thelamp-generated temperature drop below a desirable degree. Tothis end, small resistance heaters 7ll (FIGS. 1 and 2) are mounted inthe front, larger portions of the passages 53 just behind the nozzles52. These heaters may be of the kind commonly used in hairdryers capableof very rapid warm-up, being of low cost, and of modest powerconsumption. By having one of the heaters 71 suspended as by means of abracket 72 from the associated passage roof panel portion 54 and locatedadjacent to and substantially centered relative to the adjacent blowernozzle 52, extremely efficient heating of the drying air driven into andthrough the duct system is attained immediately on start-up of themachine so that by the time the copy sheet has travelled through itsdelivery path, exposure zone and the developer tray 23 and emerges frombetween the feedout rollers 24, the air issuing from the ports 60 and 69has reached a satisfactory drying temperature. Then, as the illuminationlamp heat builds up and is added to the heat produced by the heater 7ll,and the temperature of the drying air reaches the maximimum degreeconsidered safe for the purpose, the heaters 71 are deenergized byoperation of any preferred form of thermally actuated switch 73 locatedat a suitable point downstream from the heaters and desirably in thedelivery port area of the duct system. it will be understood, of course,that the electrical resistance heaters 7ll and the control thermalswitch 73 which may be a conventional thermostatic switch, will beconnected in an electrical operating circuit for the machine, whichcircuit includes the motors St) for the blower fans 49, the electricalilluminating lamp llll, the corona discharge device 211 and all otheroperating and control devices for the machine including drive motor forthe conveyor roller systems, liquid toner pump where desired, and thelike, and including suitable control switches.

It will be understood that variations and modifications may be effectedwithout departing from the spirit and scope of the novel concepts ofthis invention.

We claim as our invention:

ll. ln a copymalting machine including a chamber providing a documentscanning zone and having an illumination lamp therein, an exposure zone,means for transporting copy sheets through said exposure zone, anoptical system for translating a scanned image from the scanning zone toa copy sheet in the exposure zone, and liquid development means for theexposed copy sheets:

means for guiding the developed copy sheets from said development meansto receiving means;

a structure providing a tunnel through which the optical systemtranslates the image between said zones;

said tunnel structure including enclosure panel means facing in spacedrelation toward said guiding means;

air duct panel means located between said enclosure panel means and saidguiding means and facing toward said guiding means and with saidenclosure panel means defining an air duct system;

said air duct system including a shallow plenum duct area with a majorportion of said tunnel enclosure panel means;

blower means mounted in said scanning chamber;

a lead-in passageway along one side of the tunnel;

said passageway being of substantial cross sectional flow area at an endnear said chamber and at said end communicating with said blower toreceive air from within said chamber impelled by said blower into thepassageway;

said passageway opening along its length into said plenum duct area anddelivering the air from the passageway into the plenum duct area; and

said duct panel means in said plenum duct area having means fordirecting air from the plenum duct area toward said guiding means fordrying copy sheets after the sheets leave said development means inmovement along said guiding means.

2. A copymaking machine according to claim ll, including a secondpassageway along an opposite side of said tunnel and also communicatingin air delivering relation along its length with said plenum duct area,and another blower in said chamber drawing air from within the chamberand discharging into said another passageway for delivery of the airthrough said another passageway into the plenum duct chamber in additionto the air from said passageway along said one side of the tunnel.

3. A copymaking machine according to claim 1, including start-up heatingmeans in said duct system, and means for controlling said heating meansto maintain proper heat level in the drying air correlated with the heatgenerated by said lamp in the air drawn by said blower means from withinsaid scanning zone chamber.

4. A copymaking machine according to claim 1, including a cabinet havingsaid document scanning zone chamber in the forward upper portionthereof, means enabling air circulation into said chamber for coolingsaid scanning zone by operation of said blower means, said blower meanscomprising a blower having its intake within said chamber and providedwith a discharge nozzle delivering into said passageway said duct panelmeans underlying said tunnel panel means and including a portionproviding closure for the bottom of said chamber spaced above a copysheet receptacle, and means below said duct panel means providing adeveloped sheet delivery chute extending from said development means tosaid receptacle.

5. A copymaking machine according to claim 4, wherein said duct panelmeans include a combination duct end closure and copy sheet deflectorhaving perforations therein through which air is discharged initiallyonto the developed copy sheets on leaving the development means andcooperating with a rear end portion of a main panel to deflect developedcopy sheets downwardly therefrom.

6. A copymaking machine according to claim 4, wherein said blower meanscomprise a pair of blowers which are located at respectively oppositesides in the lower portion of said scanning zone chamber, said opticalsystem including a lens assembly centrally located at the chameber endof said tunnel and with the image path extending centrally through thetunnel to said exposure zone which is located at an opposite end of thetunnel, said tunnel panel means including a central portion underlyingsaid optical image path and respective passage formations upwardlyoffset relative to said cen-- tral portion and defining with said ductpanel means said passageway longitudinally along one side of the tunneland a second passageway longitudinally along an opposite side of saidtunnel communicating with a duct plenum space between said centralportion and said duct panel means, said blowers respectively discharginginto chamber ends of said passageways.

7. A copymaking machine according to claim 6, wherein said passageformations progressively diminsh in cross sectional flow area from saidchamber ends thereof to adjacent said discharge means.

8. A copymaking machine according to claim 6, including start-up heatingmeans in each of said passages.

9. A copymaking machine according to claim 8, said heaters comprisingelectrical resistance heaters mounted in the path of discharge from theblower nozzles and adjacent thereto, and thermal switch means in saidduct system for controlling said heaters.

10. In a copymaking machine including achamber providing a documentscanning zone, an exposure zone spaced from said scanning zone, meansfor transporting a copy sheet through said exposure zone, an opticalsystem for translating scanned images from said scanning zone to copysheet in said exposure zone, liquid development means for exposed copysheets, and means for transporting the developed copy sheets from saiddcvclopment means;

a tunnel structure through which the optical means translates the iamgebetween said zones including an enclosure panel;

panel means located between and facing toward both said transportingmeans and said enclosure panel and defining an air duct system with saidenclosure panel and including means for directing drying air toward saidtransporting means onto the developed copy sheets as transported fromthe development means;

said air duct system including passages at each side of said tunnelstructure leading to a common plenum between said passages at said airdirecting means; and

respective blowers discharging into said passages.

11. A copymaking machine according to claim 10, said enclosure panelhaving side marginal portions thereof partially separated alonglongitudinal lines, and spacer and closure plate means secured to andbetween the severed edges and offsettingsaid marginal portions to defineenclosure panel portions of the passages of larger cross sectional flowarea at inlet ends into which the blowers discharge, said passagesprogressively diminshing in cross sectional flow area from said inletends to said air directing means.

12. A copymaking machine according to claim 11, including respectiverapid warmup resistance heaters mounted in said passages adjacent to theinlet ends, and thermally responsive means in said passages downstreamfrom said inlet ends for controlling said heaters.

13. A copymaking machine according to claim 10, said panel meansincluding respective multi-aperture ported plate areas generally alignedwith said passages and providing at least a portion of said airdirecting means.

14. A copymaking machine according to claim 13, including additionalplate area in downstream relation to said ported areas and having apattern of air direction apertures supplemental to the ported areas.

15. A copymaking machine according to claim 14, said downstream platearea including means for deflecting the .copy sheets from saiddevelopment means past said air directing means.

16. In a copymaking machine including document scanning and copy sheetexposing means with a light tunnel structure operatively connecting thescanning and exposure means, liquid development means for exposed copysheets, and means for transporting the developed copy sheets from saiddevelopment means;

said tunnel structure including an enclosure panel extending therealongand spaced from said transporting means;

air motivating means; and

panel means located between said enclosure panel and said transportingmeans and defining with said panel an air duct system into which saidair motivating means drives air;

said panel means including means for directing air toward saidtransporting means in drying relation to copy sheets leaving saiddevelopment means; and

said air directing means including successive spaced areas of airdirecting ports.

combination duct closing sheet deflecting and air directing means plateattached to said tunnel panel and lappingly engaging said edge, saidplate having air directing ports therein and also having spacer ribsbetween said ports to limit contact of copy sheets therewith.

1. In a copymaking machine including a chamber providing a documentscanning zone and having an illumination lamp therein, an exposure zone,means for transporting copy sheets througH said exposure zone, anoptical system for translating a scanned image from the scanning zone toa copy sheet in the exposure zone, and liquid development means for theexposed copy sheets: means for guiding the developed copy sheets fromsaid development means to receiving means; a structure providing atunnel through which the optical system translates the image betweensaid zones; said tunnel structure including enclosure panel means facingin spaced relation toward said guiding means; air duct panel meanslocated between said enclosure panel means and said guiding means andfacing toward said guiding means and with said enclosure panel meansdefining an air duct system; said air duct system including a shallowplenum duct area with a major portion of said tunnel enclosure panelmeans; blower means mounted in said scanning chamber; a lead-inpassageway along one side of the tunnel; said passageway being ofsubstantial cross sectional flow area at an end near said chamber and atsaid end communicating with said blower to receive air from within saidchamber impelled by said blower into the passageway; said passagewayopening along its length into said plenum duct area and delivering theair from the passageway into the plenum duct area; and said duct panelmeans in said plenum duct area having means for directing air from theplenum duct area toward said guiding means for drying copy sheets afterthe sheets leave said development means in movement along said guidingmeans.
 2. A copymaking machine according to claim 1, including a secondpassageway along an opposite side of said tunnel and also communicatingin air delivering relation along its length with said plenum duct area,and another blower in said chamber drawing air from within the chamberand discharging into said another passageway for delivery of the airthrough said another passageway into the plenum duct chamber in additionto the air from said passageway along said one side of the tunnel.
 3. Acopymaking machine according to claim 1, including start-up heatingmeans in said duct system, and means for controlling said heating meansto maintain proper heat level in the drying air correlated with the heatgenerated by said lamp in the air drawn by said blower means from withinsaid scanning zone chamber.
 4. A copymaking machine according to claim1, including a cabinet having said document scanning zone chamber in theforward upper portion thereof, means enabling air circulation into saidchamber for cooling said scanning zone by operation of said blowermeans, said blower means comprising a blower having its intake withinsaid chamber and provided with a discharge nozzle delivering into saidpassageway said duct panel means underlying said tunnel panel means andincluding a portion providing closure for the bottom of said chamberspaced above a copy sheet receptacle, and means below said duct panelmeans providing a developed sheet delivery chute extending from saiddevelopment means to said receptacle.
 5. A copymaking machine accordingto claim 4, wherein said duct panel means include a combination duct endclosure and copy sheet deflector having perforations therein throughwhich air is discharged initially onto the developed copy sheets onleaving the development means and cooperating with a rear end portion ofa main panel to deflect developed copy sheets downwardly therefrom.
 6. Acopymaking machine according to claim 4, wherein said blower meanscomprise a pair of blowers which are located at respectively oppositesides in the lower portion of said scanning zone chamber, said opticalsystem including a lens assembly centrally located at the chameber endof said tunnel and with the image path extending centrally through thetunnel to said exposure zone which is located at an opposite end of thetunnel, said tunnel panel means including a central portion underlyingsaid optical image path and respective passage formations upwardlyoffsEt relative to said central portion and defining with said ductpanel means said passageway longitudinally along one side of the tunneland a second passageway longitudinally along an opposite side of saidtunnel communicating with a duct plenum space between said centralportion and said duct panel means, said blowers respectively discharginginto chamber ends of said passageways.
 7. A copymaking machine accordingto claim 6, wherein said passage formations progressively diminsh incross sectional flow area from said chamber ends thereof to adjacentsaid discharge means.
 8. A copymaking machine according to claim 6,including start-up heating means in each of said passages.
 9. Acopymaking machine according to claim 8, said heaters comprisingelectrical resistance heaters mounted in the path of discharge from theblower nozzles and adjacent thereto, and thermal switch means in saidduct system for controlling said heaters.
 10. In a copymaking machineincluding a chamber providing a document scanning zone, an exposure zonespaced from said scanning zone, means for transporting a copy sheetthrough said exposure zone, an optical system for translating scannedimages from said scanning zone to copy sheet in said exposure zone,liquid development means for exposed copy sheets, and means fortransporting the developed copy sheets from said development means; atunnel structure through which the optical means translates the iamgebetween said zones including an enclosure panel; panel means locatedbetween and facing toward both said transporting means and saidenclosure panel and defining an air duct system with said enclosurepanel and including means for directing drying air toward saidtransporting means onto the developed copy sheets as transported fromthe development means; said air duct system including passages at eachside of said tunnel structure leading to a common plenum between saidpassages at said air directing means; and respective blowers discharginginto said passages.
 11. A copymaking machine according to claim 10, saidenclosure panel having side marginal portions thereof partiallyseparated along longitudinal lines, and spacer and closure plate meanssecured to and between the severed edges and offsetting said marginalportions to define enclosure panel portions of the passages of largercross sectional flow area at inlet ends into which the blowersdischarge, said passages progressively diminshing in cross sectionalflow area from said inlet ends to said air directing means.
 12. Acopymaking machine according to claim 11, including respective rapidwarmup resistance heaters mounted in said passages adjacent to the inletends, and thermally responsive means in said passages downstream fromsaid inlet ends for controlling said heaters.
 13. A copymaking machineaccording to claim 10, said panel means including respectivemulti-aperture ported plate areas generally aligned with said passagesand providing at least a portion of said air directing means.
 14. Acopymaking machine according to claim 13, including additional platearea in downstream relation to said ported areas and having a pattern ofair direction apertures supplemental to the ported areas.
 15. Acopymaking machine according to claim 14, said downstream plate areaincluding means for deflecting the copy sheets from said developmentmeans past said air directing means.
 16. In a copymaking machineincluding document scanning and copy sheet exposing means with a lighttunnel structure operatively connecting the scanning and exposure means,liquid development means for exposed copy sheets, and means fortransporting the developed copy sheets from said development means; saidtunnel structure including an enclosure panel extending therealong andspaced from said transporting means; air motivating means; and panelmeans located between said enclosure panel and said transporting meansand defining with said panel an air duct system inTo which said airmotivating means drives air; said panel means including means fordirecting air toward said transporting means in drying relation to copysheets leaving said development means; and said air directing meansincluding successive spaced areas of air directing ports.
 17. Acopymaking machine according to claim 16, wherein the downstream areahas ports which are larger than the ports in the upstream area.
 18. Acopymaking machine according to claim 16, wherein said panel meansdefining the duct with the tunnel enclosure panel comprise a principalpanel having an edge adjacent to said developing means, and acombination duct closing sheet deflecting and air directing means plateattached to said tunnel panel and lappingly engaging said edge, saidplate having air directing ports therein and also having spacer ribsbetween said ports to limit contact of copy sheets therewith.